I've had this conversation with a lot of folks, you don't have to be an expert to write a blog post. Some of the most common and valuable ones were how I learned x or y. There are a lot more beginners out there than experts.

> Almost inevitably you will get comments about how your approach is bad or simply invalid.

Have you considered that this is probably just the anxiety talking? In my experience people don't go out of their way to be mean. Unless you specifically choose to be controversial, the worst case is people will be indifferent and just won't share/upvote.